Planning with SIVACON 8 PS - Siemens

Further information about planning7.6 Magnetic fields7.6 Magnetic fieldsGeneral informationDue to their physical characteristics, busbars designed for power distribution andtransmission generate pulsating electromagnetic fields in their vicinity with a fundamentalfrequency of 50 Hz. These magnetic fields can impair the ability of sensitive equipment suchas computers or metering instruments to function in full working order.LimitsEMC directives and the associated standards do not set out requirements orrecommendations for the planning of busbar trunking systems. DIN VDE 0100-710 can beconsulted in relation to busbar trunking systems used in hospitals.DIN VDE 0100-710 defines limits for line frequency magnetic fields in hospitals. Forexample, at 50 Hz, the magnetic induction around a patient's bed must not exceed thefollowing values:B= 2 x 10 -7 tesla for EEGB= 4 x 10 -7 tesla for ECGThe limit for inductive interference between multi-core cables and lines in a high voltageinstallation (conductor cross section > 185 mm 2 ) and the patient beds to be protected issignificantly undershot if the minimum clearance of 9 m recommended in DIN VDE 0100-710is complied with.When using busbars, this clearance can generally be reduced, since the busbar systems aredesigned to effectively reduce the magnetic interference fields in the local vicinity.Magnetic field measurementsHowever, in order to facilitate evaluation of the busbars to be used, extensive magnetic fieldmeasurements have been taken in accordance with EN 60439-2. The magnetic fieldemissions of the busbar systems were measured on a straight trunking run 9.0 m long. Withthe busbars under a balanced rated current load, the magnetic fields were measures in eightdirections at intervals of 0.1 m and up to a clearance of 1 m.Figure 7-9Coordinate system for magnetic field measurementPlanning with SIVACON 8 PS262 Planning Manual, 10/2007, A5E01541101-01